This book aims to help the student discover and explore Aristotle. Most people will agree that he is not an easily accessible philosopher. If the common opinion considers Plato to be both a poet and a philosopher, Aristotle, on the other hand, is usually presented as a dogmatist and a systematizer. Such a view is too much of an exaggeration. Aristotle, in fact, thought that the philosophical task consists as much in the definition of problems, the examination of various points of view, the exploration of difficulties, as well as in proposing solutions. And his thought, like Plato's, developed in a gradual evolution. And, however arduous it may seem to approach his writings, there is no substitute for the meticulous reading of them for the study of his philosophy. The role that the author of this book assumes is simply that of a mere intermediary between Aristotle himself and a reader of the twenty-first century.